date, beginning even before the Conquest. However, the proliferation of castles in Wales dates only from its English conquest, though a few stone castles date from the reign of Llywelyn the Great. Motte-and-bailey castles existed from before the thirteenth century in those parts of Wales which fell under English authority and they spread in south Wales after its conquest, but the most famous encastellation of Wales occurred in the north under Edward I of England (1272–1307). His famous Edwardian concentric castles, large stoneworks with multiple rings of defences, grew up at strategic locations throughout the north and the local populace was placed securely under English authority. In this case, encastellation was the result, not of weak central authority, but of a strong royal hand and direction. Scotland In Scotland, the spread of castles came with the Normans who, in the twelfth century, began constructing castles of the motte-and-bailey type in the south, where they received royal support, especially in Galloway. At about the same time, the first stone castles appeared in the north, in Orkney, built not by Normans but by the Norse. Ireland In Ireland, as in Britain and most of Europe, encastellation was primarily a Norman venture. The first castles were motte-and-baileys built on the expanding frontier of the English Pale and within it to control the local population, according to Gerald of Wales. Stone castles were slow to develop, appearing in the late thirteenth century. Germany As in France, so in Germany: the impetus for encastellation was provided, not by a strong monarch, but by the weakening of royal authority. During the eleventh-century Investiture Controversy in Germany and the resulting decline of the royal power, castle-building exploded as local warlords staked claims to formerly royal prerogatives in their petty states. In Prussia, during the Drang nach Osten and the Northern Crusades of the twelfth and thirteenth centuries, encastellation was the result of the Margraves of Brandenburg and the Teutonic Knights, who, among others, conquered the land from the pagan Prussians. The construction of castles to control territories occurred at a late point in the development of the castle and these fortresses were large and complex. They were called Ordensburgen and they served as headquarters and training grounds for initiates into the knightly orders. Notes Sources Gravett, Christopher, and Nicolle, David. The Normans: Warrior Knights and their Castles. Osprey Publishing: Oxford, 2006. Incastellamento. Hariulf. Gesta ecclesiae Centulensis. Painter,